Cozy and lovely, there’s nothing quite like a woodstove to fire the imaginations of Mammoth’s winter visitors and locals alike.

Unfortunately, town fire department leaders, along with Building Inspector John Goetz, say the stoves, specifically woodstove inserts, also are a potential hazard.

Together, the Mammoth Lakes Fire District and Goetz have proposed a set of sweeping new rules for replacing the woodstove inserts, to be implemented by ordinance over a 10-year period.

“It’s a ticking time bomb,” Goetz told the Town Council on Feb. 6. “With the heat generating on a more frequent basis [in this climate], it’s just a matter of time.”

In the last 10 years, he said, there have been eight major home fires, all of them attributed to faulty woodstove inserts or their installations. No one was injured in any of the fires, he said.

Even so, Goetz and Fire Chief Brent Harper said the potential for catastrophe is so great that Mammoth needs new standards for new and reconstructed woodstove inserts.

The new ordinance, still at its draft stage, will come before the Town Council again soon, complete with tweaks to the language and any additional recommendations from Town Attorney Andrew Morris.

The sooner the better, Goetz argued in his presentation.

In a study that took a year for him and the fire district to complete, Goetz said he looked at 17 woodstove inserts in one older condominium project and found 11 of them to be unsafe. In another, he inspected 60 units and 27 of them had problems with woodstove inserts.

The problem, he said, was a phenomenon called pyrolysis.

Wood stoves situated too close to combustible materials (usually in back of, or alongside the inserts) causes a chemical change in the wood, lowering the temperature required to make it catch on fire by spontaneous combustion.

Research on the web indicates a normal piece of 2x4 will spontaneously ignite at 600 degrees F. If the wood stove or flue pipe is too close, it will draw the moisture from the 2x4. When this happens repeatedly, the piece of wood can spontaneously ignite as low as 200 degrees F.

Generally, experts say, this happens in three to five years. The wood stove can be used for years without a problem, and then suddenly there is a fire.

In Mammoth, woodstoves get a real workout.

“In our climatic zone, where we burn fires far more frequently than a person in Southern California,” Goetz said, “the heat that’s generated in a prefabricated firebox has created an incredible amount of pyrolysis.”

Although there is no way to know for sure, Goetz estimated there are between 2,000 to 4,000 woodstove inserts in homes or condos in Mammoth. Most of them have been installed into an existing, open-faced fireplace.

To replace them is expensive, said Harper, and would require up to 10 years for all the woodstove inserts to be replaced by the four contractors in town who do such work.

“I’d like to swap them all out,” Harper said, “but it does run between $8,000 and $10,000 depending on the facade that’s on the front of each fireplace, so it’s pretty expensive.

“Obviously our community relies on people coming here and being able to burn a fire, not only for the heat, but also for the ambiance.”

Under the terms of the proposed ordinance, which Goetz conceded is tougher than California’s statewide regulations, property owners would have 10 years to replace the inserts or face penalties levied by either the town or the fire district.

Council member John Eastman questioned why it would take so long.

“All our contractors are amazing contractors, and they can get three to four done per week,” Goetz said, “but it’s still a checkbook that’s involved. To lessen the pain, we gave people time. From my point of view, we’re comfortable with the 10-year time frame.”

A far less expensive alternative, he said, would be to replace the insert with a pellet stove. That way, the façade of the fireplace would not have to come down.

But that’s where the ambiance factor comes into play, Harper said.

For guests who want a winter experience, or for locals who have come to like their woodstoves over the years, the idea of not having a fire roaring in the woodstove just wouldn’t cut it.